Sewing machine presser mechanism



July 21, 1 KOSUKE KAGlYAMA 3,141,430

SEWING MACHINE PRESSER MECHANISM 2 Sheets-Sheet 1 Filed Dec. 14, 1962 INVENTOR AflSl/Ai A64 a/XAMA i M. 1m ATTORNEY.

July 21, 1 KOSUKE KAGIYAMA 3,141,430

SEWING MACHINE PRESSER MECHANISM Filed Dec. 14, 1962 2 Sheets-Sheet 2 INVENTOR: A OS'UA F AAG/Y/I M14 BY 2 M ATTORNEY United States Patent 3,141,430 SEWING MACHINE PRESSER MECHANISM Kosuke Kagiyama, 3938 Obihonmachi, Nichinan-shi, Miyazald-ken, Japan Filed Dec. 14, 1962, Ser. No. 244,738 Claims priority, application Japan Dec. 22, 1961 3 Claims. (Cl. 112-237) This invention relates to sewing machines and more particularly concerns improvements in a presser foot mechanism of a type suited for application to small-size sewing machines.

The object of this invention is to dispense with the compression coil spring coventionally used in the presser mechanism, by constructing the presser rod and foot integrally, by attaching a spring wire to the top end of the integral construction of the presser rod and foot, and by arranging the said spring so as to be moved manually for raising and lowering the presser rod and foot, alternately. Another object of this invention is to eliminate the needle support conventionally employed, by arranging the needle holder to make its vertical reciprocating motion along, and as guided by, the presser rod. Still another object of this invention is to provide a simplified construction of the work presser mechanism suitable for application to small-size machines.

An embodiment of the invention will be explained in detail hereinafter with reference to the accompanying drawings, in which:

FIG. 1 shows in elevation the small-size sewing machine having a presser mechanism constructed according to the present invention.

FIG. 2 shows the sewing machine of FIG. 1 in a plan view.

FIG. 3 represents a perspective view of the presser mechanism used in the sewing machine of FIGS. 1 and 2.

FIG. 4 represents a perspective view of the needle actuating mechanism used in the said small-size sewing machine.

FIG. 5 depicts the thread take-up mechanism in a perspective view.

FIG. 6 shows the details of a part of the transmitting mechanism for the shuttle driving and the work feeder driving shaft in a side view.

As shown in FIGS. 1 and 3, the presser mechanism embodying the present invention consists essentially of presser foot 14a integral with presser rod 14, spring wire 17 integrally joined with coupling member 16, and two fixed pins 18, 21 which serve to support the spring wire 17 at its distal portion. The coupling member 16, being integrally joined to the spring wire 17, is in effect an extension of the wire 17. Adjacent to the upper end of the presser rod 14 is rigidly located the pin 15, forming a cross pattern together with the said rod and serving as the pivot pin movably connecting the coupling member 16 to the presser rod 14. The wire spring 17, extending from the coupling member 16, is bent downwardly and includes at least one convolution 17a wound around a fixed pin 18. The free end portion of the wire spring 17 bears against another fixed pin 21. The wire spring 17 is preloaded or continuously stressed so that, in normal operation, it yieldingly applies downward force to the coupling member 16 and, hence, to presser rod 14, thus causing the presser foot 14a yieldingly to hold down under pressure a workpiece placed on the work table 3, which is connected to a main frame 2 on a bed plate 1.

Apart from the above mechanism, means of applying upward force manually to the spring wire 17 is provided on the machine frame, as can be seen in FIGS. 1, 2 and 3, for raising the presser rod 14 and its foot 14a away from the work table 3 in order to remove a finished workpiece or to place a new workpiece to be stitched on the work table. The means consists of rotary shaft 19 which is to be rotated manually by a knob 19a mounted thereon and which is integral with an arm 20 having a protruding tab 20a positioned in such a way as to engage, and apply upward force to, the spring wire 17 from its underside when the rotary shaft 19 is manually rotated.

Other parts of the sewing machine provided with the mechanism of the foregoing description will be explained hereunder in order that the function of the mechanism will be better understood from the over-all viewpoint.

The driving motor 40 of the sewing machine is pivotally supported in the ends of the brackets 47 by means of a horizontal spindle 46 and the side frames 45 of the said motor, there being one side frame and one bracket on each side. Another spindle 48, borne in the other ends of brackets 47, is integrally provided with an eccentric cam 49 at its intermediate part and a knob 50 at its end. The cam 49 is engaged in a groove 51 formed by two studs extending from the lower part of the motor 40, such that, when the knob 50 is manually rotated, the rotation of the eccentric cam 49 causes the motor to move angularly and around the horizontal spindle 46, thus displacing the drive shaft 41 and its pulley 42 with respect to the main shaft 4 of the machine and its pulley 44. This displacement slackens the drive belt 43 to interrupt the transmission of drive from motor to main shaft. In other words, the eccentric cam 49 and its associated parts constitute a means of establishing or interrupting the drive as desired.

Referring to FIG. 4, main shaft 4 integrally carries an eccentric wheel 7 which is engaged in the long slot 6 cut out in the lever 9. This lever is movably held by pin 8 and connected, by means of linkage pins 5, 13, to holder 11 carrying thread needle 10 on one hand and to the connecting piece 12 on the other.

In operation, as the main shaft rotates, its eccentric wheel 7 imparts oscillating motion to lever 9 which then rocks on its pin 8, and this rocking motion causes holder 11 on one hand connecting piece 12 on the other to reciprocate in vertical direction. The up and down motion of holder 11 is guided by the presser rod 14 aforementioned.

The parts working in conjunction with the connecting piece 12 are shown in FIG. 6. The lower end of the piece 12 is movably connected through pin 32 to rocker 33 which is arranged to rock around its pin 34 when the piece 12 reciprocates vertically. The rocker 33 is associated with the shuttle driving shaft 24 by means of arm 37 mounted on this shaft and having a pin 36 engaged in the notch 35 of the rocker, and also with the feeder driving shaft 23 by means of arm 33 mounted on this shaft and arranged to be move by a protruding part of rocker 33. The shaft 23 with a spring plate 39, made to rotate to and fro by rocker 33 in operation, actuates feeder dog 25 to give feeding motion to the work being sewn in the manner hitherto known. The shaft 24 similarly actuates the shuttle mechanism in a casing 26.

The thread taker 29, having a thread hole 29a at its free end, is pinned to the crank lever 27 at the other end by means of pin-28 and also to the radius piece 31 by means of pin 30 at its intermediate part, the radius piece being pivoted on the machine frame by means of fixed pin 18, all as shown in FIG. 5. Since the crank lever 27 is rigidly mounted on the main shaft 4, the rotation of this shaft causes the lever to crank the taker 29 around pin 30 whose position varies along the orbit described by the outer end of the radius piece 31 which is pivoted on the fixed pin 18. Thus, the composite motion involved in this cranking causes the free end of the taker 29 to oscillates vertically so that the thread leading through its hole 29a to needle 10 becomes tightened and slackened alter- 3 nately in the manner desired for the sewing operation.

What I claim is:

1. In a sewing machine comprising work feeding and stitch forming means, the improvement which comprises the provision of a vertically movable presser rod; a presser foot rigidly connected to the lower end of said rod; a first fixed pin; an elongated spring member formed of flexurally resilient wire, said spring member having a convolution formed therein intermediate its ends, said convolution being Wound around said first fixed pin; a second fixed pin against which one end portion of said spring bears; coupling means connecting the other end portion of said spring to the upper end portion of said rod, said spring being continuously stressed to urge said rod yieldingly downwardly for causing guiding engagement between a workpiece and said resser foot, and manually operable means engageabie with said spring intermediate said convolution and said other end thereof to force said 4 spring against the stressing thereof for raising said presser foot.

2. The improvement according to claim 1, wherein said stitch forming means comprises a needle, said improvement further comprising the provision of needle carrying means slidably mounted on said presser rod.

3. The improvement according to claim 1, wherein said coupling means is effectively an integral extension of said other end portion of said spring.

References Cited in the file of this patent UNITED STATES PATENTS 1,191,232 Richards July 18, 1916 1,191,233 Richards July 18, 1916 1,542,871 Grieb June 23, 1925 1,749,529 Feigel Mar. 4, 1930 2,385,768 Althens Oct. 2, 1945 3,036,536 Ritter May 29, 1962 

1. IN A SEWING MACHINE COMPRISING WORK FEEDING AND STITCH FORMING MEANS, THE IMPROVEMENT WHICH COMPRISES THE PROVISION OF A VERTICALLY MOVABLE PRESSER ROD; A PRESSER FOOT RIGIDLY CONNECTED TO THE LOWER END OF SAID ROD; A FIRST FIXED PIN; AN ELONGATED SPRING MEMBER FORMED OF FLEXURALLY RESILIENT WIRE, SAID SPRING MEMBER HAVING A CONVOLUTION FORMED THEREIN INTERMEDIATE ITS ENDS, SAID CONVOLUTION BEING WOUND AROUND SAID FIRST FIXED PIN; A SECOND FIXED PIN AGAINST WHICH ONE END PORTION OF SAID SPRING BEARS; COUPLING MEANS CONNECTING THE OTHER END PORTION OF SAID SPRING TO THE UPPER END PORTION OF SAID ROD, SAID SPRING BEING CONTINUOUSLY STRESSED TO URGE SAID ROD YIELDINGLY DOWNWARDLY FOR CAUSING GUIDING ENGAGEMENT BE- 